Battery maintenance is an important aspect of RV upkeep, whether you have a dumb single-stage charging converter or a multi-phase smart converter battery, fluid levels should be part of a your rig's maintenance routine.
Batteries are toast but you may be able to get them to charge a bit although they will never deliver full capacity. Find out if it was converter, lack of upkeep, and/or combination of both that caused this issue.
Either way it appears a new battery and possibly converter may be needed to properly resolve this issue. Randy @ Bestconverter.com can suggest a easily installed replacement for your current set-up.
